What I am reading

Technical - "Programing in Ruby"

This is another book from The Pragmatic Programmer publishers. This is a pretty thick book, which includes an introduction to Ruby as well as a long library reference. I've read some of the introductory chapters, but I use it mostly for reference while hacking some Ruby code.

One early program I wrote was to help my friend Jack download a bunch of MP3 files that were refernced by a specific web page. Here is the code:

require "net/http"
require "open-uri"

def get_page (uri)
 # split into parts
 uri =~ %r{http://((\w|\.)*)}
 @@domain = $1
 file = $'
 # connect to the web server and fetch the page '
 puts "-->> Connecting to domain #{@@domain}\n"
 #"
 result = ""
 Net::HTTP.start(@@domain,80) {|http|
   response = http.get(file)
   result = response.body
 }
 result
rescue
 puts "Unable to open #{uri}"
end

def download_mp3 (base_uri, file)
 u = base_uri + file
 # Replace blanks by _ in file name
 fname = file.gsub("%20", "_")
 if (File.exists?(fname))
   puts "--> Already have #{fname}"
 else
   puts "--> Saving <#{fname}>"
   f = File.open(fname, "w");
   u = OpenURI.open_uri(u)
   f.write(u.read) 
 end
rescue
 puts "Unable to save #{fname}"
end

if (ARGV.length == 0)
 puts "Usage: get_mp3.rb "
else
 base_uri = ARGV[0]
 page = get_page(ARGV[0])
 count = 0
 page.scan(%r{<a href=((.)(.)*\.mp3)}) {
   download_mp3(base_uri, $1[1..-1])
   count += 1
 }
 puts ">>> Downloaded #{count} files...\n"
end

This program probably could be made shorter, but it does work. I had fun trying to come up with proper regular expression.

This book is "the" Ruby reference at this point and I have so far only scratched the surface. Meanwhile I'm working on another project with Ruby and Ruby on Rails - a program to index MP3 files.

posted by richieb @ 7:39 PM